Alkene stability increases with the degree of alkyl substitution on the double bond due to hyperconjugation and inductive stabilization effects.
Analyzing each structure:
I is tetrasubstituted (4 alkyl groups attached to the two sp² carbons), the most stable.
III appears to be a disubstituted alkene with specific geometry providing enhanced stability.
II is trisubstituted (3 alkyl groups and 1 hydrogen).
IV is also disubstituted but with different geometry, less stable than III.
The decreasing order of stability: tetrasubstituted > trisubstituted > disubstituted variations.
Therefore: I > III > II > IV.
